1. Field of the Invention
The invention relates to a device for separating a heavy fraction from a fluid, comprising: a main channel, surrounded by a substantially cylindrical housing; swirl means, positioned in the main channel, for transferring a rotating movement component to the fluid moving through the main channel; collecting means, which in radially direction to openings in the cylindrical housing adjoin to the main channel, for collecting the discharged heavy fraction; a concentric additional supply conduit, provided with an outlet, which additional supply conduit at least partly extends into the cylindrical housing; a return channel, which connects the collecting means with the additional supply conduit; and the additional supply conduit is provided with deflection means, which are positioned downstream of the outlet, for providing a movement component in radial direction to the returning fluid fraction moving through the return channel. The invention also relates to a method for separating a heavy fraction from a fluid, comprising the steps: A) supplying the fluid through a main channel and providing the fluid with a rotational movement component; B) discharging a heavy fraction of the fluid through openings in the wall of the main channel; and C) returning at least a part of the heavy fraction as discharged during step B) via a return channel to an additional supply conduit which is coaxially positioned in the main channel.
2. Description of the Prior Art
The U.S. Pat. No. 7,163,626 discloses a device for treating a gas/liquid mixture, also referred to as a “demister”, provided with: an inlet, an outlet, rotating means arranged in a tube between the inlet and the outlet to realise a separating cyclone, one or more outlet openings in the tube downstream the rotating means to allow a part of the mixture to flow laterally out of the tube, a return conduit arranged in axial direction through the rotating means for reintroducing in the tube the flow which has exited via the outlet openings and divergence means arranged close to the outlet opening of the return conduit for allowing the reintroduced flow to diverge laterally. The advantage of the return conduit in the separating device debouching at a location axially in the tube is that it enables a lighter component present in the heavier fraction discharged to the tube to a renewed separating process. The divergence means arranged close to the outlet opening of the return conduit cooperate with the outlet opening of the return conduit that is usually arranged in the centre of the tube. As the mixture has a substantially axial speed component in the centre of the tube (the centre of the cyclone) creep may occur along the return conduit whereby liquid droplets are introduced in the (centre of) the outlet flow. To enhance the capacity of the separating device (e.g. to enable working a increased pressure and/or with increased flow quantities) in U.S. Pat. No. 7,163,626 divergence means are introduced for allowing the reintroduced flow to diverge laterally and for allowing creep that occur along the return conduit to diverge laterally.